The demands of computer and recording technology for high speed, fast access recording devices has spurred the development of disc type recording devices. In these devices, the magnetic material is embedded in the surface of a disc shaped plate which is then rotated at high speed. One or more recording heads may operate in proximity to the upper and/or lower surface of the disc. The discs are manufactured to high tolerances but nevertheless have sufficient surface roughness to entrap a considerable film of air which then moves with the surface of the disc. Conventional recording heads have been designed to ride on this thin film of air, supporting the delicate transducer a small fraction of an inch away from contact with the disc. Thus, while the head "flys" about the surface of the disc, there is no wear on the head or associated parts. However, if the head is allowed to "fly" too high above the disc surface, poor frequency response and data resolution will be obtained and it is therefore necessary to bias the head toward the surface of the disc to keep the height to a minimum.
As described above, the normal operational situation is essentially non-wearing, however, there are two situations which are difficult to avoid in practice, that may cause severe damage and provoke eventual failure in conventional heads. The first situation results from the variations in surface roughness from one manufacturer to another, or even among different discs from the same manufacturer. This differentiation in surface roughness creates a differentiation in the depth of the laminar film pulled along by the rotating discs and therefore causes a variation in the flying height of the recording head. Consequently, a bias toward the disc surface that produces a proper flying height in one manufacturers disc, may force the head so close to the disc surface of another manufacturer that the head will strike asperities on the surface of the disc. The second situation is that the heads may be damaged by contact with the disc surface caused by vertical oscillations induced in the transducer head, by vertical variations in the disc surface. These variations are present in the discs of all manufacturers to a greater or lesser extent and causes the transmittal of a vertical force to the recording head by the action of the laminar film layer. The vertical variation may eventually induce an oscillation in the head of increasing amplitude until the amplitude is such that it causes a striking contact with the surface of the disc and consequential head damage.
Prior art devices make no provision for accommodation of the transducer apparatus to a range of surface roughness. Further they have no provision to obviate the tendency toward oscillation. In fact, a conventional design is arranged with point contact between the head support means and the biasing means thus allowing any tendency toward amplifying oscillation to proceed without interference.
The frame design of some prior devices required complex machining and other manufacturing operations resulting in high cost. Additionally, there is usually no provision for making the device adaptable to different mountings, or to facilitate assembly with the other elements of the apparatus.